Abstract:
Histamine is a central neurotransmitter, it increases arousal via H1 receptors. This study
examines the effect of ultra-diluted histamine on arousal through changes in the sleep
pattern of Wistar rats. The spectral density in delta (0.5–2.5 Hz) band, one of the three
major spectral components of the sleep-electroencephalogram, was analyzed against
time. Rats were randomized to receive histamine 30c (histamine 30c, 0.05 ml every
20 min during the first 2 h orally), histamine intraperitoneal pre-treatment/histamine
30c (histamine 6 mg/kg i.p., followed by histamine 30c) or solvent control. The mean
delta band spectral density was lower in the histamine 30c and histamine pretreatment/histamine 30c groups than the control group. Significant differences between
histamine 30c and baseline during the first 2 h imply an immediate effect. These results
also suggest a dynamic process in which the system spontaneously evolves between
two locally stationary states according to a power law. From the time perspective, the
system approaches, asymptotically, an equifinal state.